In conversation at work yesterday, we were discussing the possibility of making some customizations to Firefox. This reminded me of the powerful, though well hidden, about:config file. It seems most users are not even aware of the existence of this file.
Firefox's about:config allows such changes as adjusting the amount of memory used for cache, enabling encryption with RSA authentication, and defining specific rules for the handling of cookies. Some of the setting available through about:config can be modified through the tools menu. There is usually a comment stating that changes can be made from the tools menu instead. In order to access about:config simply type about:config into the URL bar and hit enter. Doing so will bring up many pages worth of options. From about:config changes to networking, installation, browsing, saving, and security can be made, along with other things. There are even BiDi (bi-directional text) changes that can be made. For those users interested in appearance there are also options for customizing hyperlink colors, previously viewed colors, and the browser's background along with other options. Delving into all the available prefrences and the details of what each of them does is beyond the scope of this brief overview. Refer to mozillaZine for details on what each preference modifies.
Changes made via about:config, the tools menu, or by some extensions are kept in the prefs.js file. My prefs.js file is found in ~/.mozilla/firefox/6eawc2od.default/prefs.js though this may vary depending on your system. Although preference changes may also be made through the prefs.js file it is more prone to mistakes which have the potential to make Firefox unusable. This brings us to the usual warning that all files should be backed up before making changes. One advantage that the prefs.js file has over the other editing methods is the ease at which many profiles can be changed simultaneously simply by copying prefs.js for other users. An administrator can tighten Firefox's security settings via about:config then copy the prefs.js file across as many home directories and/or systems as desired.
Having so many options makes Firefox an even more appealing choice for web browsing. The inclusion of about:config and prefs.js gives powerusers the performance and security changes they crave and end users a vast amount of style configurations to try.
